Semiconductor device

ABSTRACT

In the semiconductor device, a bump electrode which connects a semiconductor chip and a wiring board is made up of a first part surrounded by an insulating film and a second part exposed from the insulating film. Since it is possible to reduce a width of the bump electrode while increasing a height of the bump electrode, a distance between the neighboring bump electrodes can be increased, and a filling property of a sealing material can be improved.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2015-193117 filed on Sep. 30, 2015, the content of which is herebyincorporated by reference into this application.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a semiconductor device, for example, atechnique effectively applied to a semiconductor device including asemiconductor chip having a rewiring (rearrangement wiring).

BACKGROUND OF THE INVENTION

Japanese Patent Application Laid-Open Publication No. 2014-229623(Patent Document 1) discloses a technique in which an electrode padformed on a surface of a semiconductor chip and a lead electrode of awiring board are connected via a Cu pillar.

International Publication No. 00/44043 (Patent Document 2) discloses atechnique in which bonding pads arranged in a peripheral portion of asemiconductor chip and bump electrodes arranged in an entire chipsurface area are connected by rearrangement wiring. It further disclosesa chip size package in which a semiconductor chip having bump electrodesarranged on a surface thereof is connected onto a mounting board byface-down bonding, and a gap between the semiconductor chip and themounting board is filled with underfilling resin.

SUMMARY OF THE INVENTION

The Cu pillar of the Patent Document 1 is a technique capable of copingwith an increase of the number of pins (increase of the number ofterminals) and a narrower pitch between terminals accompanying anincrease of the integration degree of the semiconductor chip. However,the bump electrode made of solder of Patent Document 2 or the like isused in the field of automotive electronics where high reliability isrequired.

In addition, a screen printing method, an electrolytic plating method, asolder ball supply method and the like may be used as a method offorming the bump electrode.

A bump electrode obtained by the solder ball supply method withexcellent controllability of a height of the bump electrode is used alsoin a semiconductor device that the inventor of the present applicationhas studied, but the following problems have been found out through thestudies by the inventor of the present application.

First, stress is applied to the bump electrode that connects asemiconductor chip and a mounting board due to a difference incoefficient of expansion therebetween, and thus, connection failure suchas disconnection of the connecting portion (bump electrode) occurs. Inorder to prevent such failure, for example, it is necessary to increasethe height of the bump electrode by using a solder ball with a largediameter. In such a case, however, since a space between the neighboringbump electrodes is decreased, avoid (unfilled portion) is generated whena gap between the bump electrodes is filled with underfilling resin, sothat the disconnection of the connecting portion or the like occurs andthe connection reliability is deteriorated. In addition, theabove-described problems become more significant when the pitch betweenterminals becomes narrower along with an increase of the number of pins.

Namely, there is a demand for the improvement in reliability in thesemiconductor device including the bump electrode.

The other problem and novel characteristics of the present inventionwill be apparent from the description of the present specification andthe accompanying drawings.

In a semiconductor device according to one embodiment, a bump electrodewhich connects a semiconductor chip and a wiring board is made up of afirst part whose periphery is surrounded by an insulating film and asecond part exposed from the insulating film.

According to one embodiment, it is possible to improve the reliabilityof the semiconductor device.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a top view of a semiconductor device according to anembodiment;

FIG. 2 is a side view of the semiconductor device according to theembodiment;

FIG. 3 is a bottom view of the semiconductor device according to theembodiment;

FIG. 4 is a partial cross-sectional view of the semiconductor deviceaccording to the embodiment;

FIG. 5 is a plan view of a semiconductor chip according to theembodiment;

FIG. 6 is an enlarged plan view of a section A in FIG. 5;

FIG. 7 is a cross-sectional view taken along a line A-A in FIG. 6;

FIG. 8 is a process flow diagram showing a part of a manufacturingprocess of the semiconductor device according to the embodiment;

FIG. 9 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device according to theembodiment;

FIG. 10 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG. 9;

FIG. 11 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG.10;

FIG. 12 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG.11;

FIG. 13 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG.12;

FIG. 14 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG.13;

FIG. 15 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG.14;

FIG. 16 is a cross-sectional view showing a principal part of amanufacturing process of a semiconductor device of Modification Example1;

FIG. 17 is a cross-sectional view showing a principal part of amanufacturing process of a semiconductor device of Modification Example2;

FIG. 18 is a cross-sectional view showing a principal part of amanufacturing process of a semiconductor device of Modification Example3; and

FIG. 19 is a cross-sectional view showing a principal part in themanufacturing process of the semiconductor device continued from FIG.18.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

In the embodiments described below, the invention will be described in aplurality of sections or embodiments when required as a matter ofconvenience. However, these sections or embodiments are not irrelevantto each other unless otherwise stated, and the one relates to the entireor a part of the other as a modification example, details, or asupplementary explanation thereof.

Also, in the embodiments described below, when referring to the numberof elements (including number of pieces, values, amount, range, and thelike), the number of the elements is not limited to a specific numberunless otherwise stated or except the case where the number isapparently limited to a specific number in principle, and the numberlarger or smaller than the specified number is also applicable.

Further, in the embodiments described below, it goes without saying thatthe components (including element steps) are not always indispensableunless otherwise stated or except the case where the components areapparently indispensable in principle.

Similarly, in the embodiments described below, when the shape of thecomponents, positional relation thereof, and the like are mentioned, thesubstantially approximate and similar shapes and the like are includedtherein unless otherwise stated or except the case where it isconceivable that they are apparently excluded in principle. The samegoes for the numerical value and the range described above.

Also, the same components are denoted by the same reference charactersin principle throughout the drawings for describing the embodiments, andthe repetitive description thereof is omitted. Note that hatching isused in some cases even in a plan view so as to make the drawings easyto see.

Embodiment Structure of Semiconductor Device

FIG. 1 is a top view of a semiconductor device according to anembodiment. FIG. 2 is a side view of the semiconductor device accordingto the embodiment. FIG. 3 is a bottom view of the semiconductor deviceaccording to the embodiment. FIG. 4 is a partial cross-sectional view ofthe semiconductor device according to the embodiment. FIG. 5 is a planview of a semiconductor chip according to the embodiment. FIG. 6 is anenlarged plan view of a section A in FIG. 5. FIG. 7 is a cross-sectionalview taken along a line A-A in FIG. 6.

As shown in FIG. 1, a semiconductor device SA according to theembodiment includes a wiring board WB having a rectangular shape (forexample, a square shape), and a semiconductor chip CHP having, forexample, a rectangular shape is mounted on a center portion of thewiring board WB via a sealing material (underfill) UF. As shown in FIG.1, a size of the semiconductor chip CHP is smaller than a size of thewiring board WB.

Next, the semiconductor device SA according to the embodiment includesthe wiring board WB, and a plurality of solder balls SB for board (boardsolder balls SB) are formed on a rear surface (bottom surface) of thewiring board WB as shown in FIG. 2. Meanwhile, the semiconductor chipCHP is mounted on a front surface (main surface, upper surface) of thewiring board WB, and a plurality of bump electrodes BE2 are formed onthe semiconductor chip CHP. A height of the bump electrode BE2 is, forexample, about 40 μm to 200 μm. Further, the semiconductor chip CHP andthe wiring board WB are electrically connected to each other throughthese bump electrodes BE2. As shown in FIG. 2, a gap between thesemiconductor chip CHP and the wiring board WB due to the presence ofthe bump electrodes BE2 is filled with the sealing material UF. Thesealing material UF is in contact with a main surface of thesemiconductor chip CHP, the front surface of the wiring board WB andside surfaces (surfaces) of the bump electrodes BE2.

Next, as shown in FIG. 3, the plurality of board solder balls SB arearranged in an array form on the rear surface of the wiring board WB.FIG. 3 shows an example in which the board solder balls SB are arrangedin four lines along an outer peripheral portion (outer edge portion) ofthe wiring board WB. These board solder balls SB function as externalconnection terminals for connecting the semiconductor device SA with anexternal device. Namely, the board solder ball SB is used for, forexample, mounting the semiconductor device SA onto a circuit boardtypified by a motherboard.

FIG. 4 is a partial cross-sectional view of the semiconductor device SAaccording to the embodiment. Although the wiring board WB has amultilayer wiring structure, FIG. 4 shows only each single layer of acore layer CL, a wiring WL1 on the front surface of the core layer CLand a wiring WL2 on the rear surface of the core layer CL. An uppersurface and a side surface of the wiring WL1 formed on the front surfaceof the core layer CL are coated with a solder resist film SR1. Aterminal TA formed in a part of the wiring WL1 is exposed from thesolder resist film SR1 through an opening provided in the solder resistfilm SR1, and the bump electrode BE2 is connected to the terminal TA inthe opening. An upper surface and a side surface of the wiring WL2formed on the rear surface of the core layer CL are coated with a solderresist film SR2. A land LND formed in a part of the wiring WL2 isexposed from the solder resist film SR2 through an opening provided inthe solder resist film SR2, and the board solder ball SB is connected tothe land LND in the opening. The wiring WL1 on the front surface isconnected to the wiring WL2 on the rear surface through a wiring WL3provided in a via penetrating the core layer CL. The solder resist filmsSR1 and SR2 are insulating films made of insulating resin, and the corelayer CL is made of a resin board including an insulating layer made of,for example, glass epoxy resin.

The semiconductor chip CHP is mounted on the wiring board WB, and thebump electrode BE2 connected to a rewiring (rearrangement wiring) RMformed on the main surface of the semiconductor chip CHP is connected tothe terminal TA exposed from the solder resist film SR1. Further, thegap between the semiconductor chip CHP and the wiring board WB is filledwith the sealing material UF. Namely, the semiconductor chip CHP ismounted on the front surface of the wiring board WB with the bumpelectrode BE2 interposed therebetween so that the main surface of thesemiconductor chip CHP opposes the front surface of the wiring board WB.Further, a gap between the main surface of the semiconductor chip CHPand the front surface of the wiring board WB is completely filled withthe sealing material UF, and each gap among the plurality of bumpelectrodes BE2 is also completely filled with the sealing material UF.In other words, a sidewall (side surface, surface) of the bump electrodeBE2 is in contact with the sealing material UF over the wholecircumference. The sealing material UF is provided in order to, forexample, mitigate stress applied to a bonding portion between the bumpelectrode BE2 and the terminal TA, and is made of an insulating resinfilm such as epoxy resin.

Pad electrodes PA are arranged in two lines on the main surface of thesemiconductor chip CHP shown in FIG. 5 along a peripheral edge portionthereof. The pad electrodes PA are arranged in two lines along each oftwo long sides and two short sides of the rectangular main surface, sothat two annular rows of the pad electrodes PA are configured. Further,a plurality of bump electrodes BE1 are arranged in a matrix form in theX direction and the Y direction on an inner side of the annular row ofthe pad electrodes PA, and a group of the bump electrodes BE1 is formedas a whole. The plurality of bump electrodes BE1 each having a circularshape are arranged at an equal pitch in the X direction or the Ydirection, and the bump electrodes BE1 in neighboring lines are arrangedin a zigzag manner. All the circles of FIG. 5 represent the bumpelectrodes BE1.

In addition, dummy bump electrodes DBE1 are arranged at corner portionsof the semiconductor chip CHP in a region on an outer side of the groupof the bump electrodes BE1 arranged in the matrix form. The ellipticaldummy bump electrode DBE1 is arranged at each of the corner portions ofthe semiconductor chip CHP, and a long axis thereof substantiallymatches a direction of the diagonal line of the semiconductor chip CHP.In other words, the long axis of the dummy bump electrode DBE1 isdirected to the corner portion of the semiconductor chip CHP. The fourellipses of FIG. 5 represent the dummy bump electrodes DBE1.

Each of the pad electrodes PA and the bump electrodes BE1 is connectedto each other via the rewiring RM (not illustrated), and the rewiring RMextends from the peripheral edge portion of the semiconductor chip CHPtoward the center. Namely, the pad electrodes PA arranged in theperipheral edge portion of the semiconductor chip CHP are re-arranged tothe bump electrodes BE1 arranged in the center area of the semiconductorchip CHP by the rewiring RM. A pitch between the neighboring bumpelectrodes BE1 is larger than a pitch between the neighboring padelectrodes PA. Each of the pitch between the neighboring bump electrodesBE1 and the pitch between the neighboring pad electrodes PA mentionedhere are those having a minimum value. By increasing the pitch betweenthe bump electrodes BE1 which function as external connection terminalsof the semiconductor chip CHP, the above-described connection with thewiring board WB is facilitated.

FIG. 6 shows the four bump electrodes BE1 of a section A of FIG. 5. Asshown in FIG. 6, the pad electrode PA is connected to the bump electrodeBE1 via the rewiring RM. Namely, one end of the rewiring RM is connectedto the pad electrode PA via openings 10 a and 11 a, and the other endthereof is connected to the bump electrode BE1 via openings 16 a and 17a. The other end (end portion) of the rewiring RM at which the bumpelectrode BE1 is arranged has a circular region (bump electrode mountingportion) having a diameter larger than a diameter of the bump electrodeBE1, and the whole (whole region) of the bump electrode BE1 is arrangedinside this circular region. In other words, the bump electrode BE1 isarranged on the rewiring RM, and does not protrude from the rewiring RM.

FIG. 7 shows a cross-sectional view taken along a line A-A of FIG. 6. Asshown in FIG. 7, the pad electrode PA is formed on the semiconductorsubstrate 1, a surface protective film 10 and a protective film 11 areformed on the semiconductor substrate 1 and the pad electrode PA. Thesurface protective film 10 and the protective film 11 have the openings10 a and 11 a that expose a part of the pad electrode PA, respectively.The opening 11 a has a larger diameter than that of the opening 10 a andopens the whole region of the opening 10 a.

The pad electrode PA is configured of a conductor film made of, forexample, an aluminum film, an aluminum alloy film (an AlSi film, an AlCufilm, an AlSiCu film or the like) or a copper film. When the padelectrode PA is formed of an aluminum film or an aluminum alloy film, ametal barrier film may be provided on and under the aluminum film or thealuminum alloy film. For example, the pad electrode PA may have astacked structure of a Ti film/a TiN film/an AlCu film/a TiN film formedin this order from a bottom layer thereof. In addition, when the padelectrode PA is formed of a copper film, a metal barrier film may beprovided under the copper film and an insulating barrier film may beprovided on the copper film. For example, the pad electrode PA may havea stacked structure of a TaN film/a Cu film/a SiCN film formed in thisorder from a bottom layer thereof.

The surface protective film 10 is made of an inorganic insulating film,and is configured of, for example, a silicon oxide film, a siliconnitride film or a stacked film thereof. Meanwhile, when the surfaceprotective film 10 is made of the stacked film, a silicon oxide film anda silicon nitride film are stacked in this order from a bottom layerthereof. It is preferable that a film thickness of the surfaceprotective film 10 is, for example, 1 μm or less.

The protective film 11 is made of an organic insulating film, and isconfigured of, for example, a polyimide film having a film thickness ofabout 3 to 5 μm. The protective film 11 has a stress mitigating functionto prevent the stress applied to the bump electrode BE1 and the rewiringRM from being propagated to the surface protective film 10 and the like.

As shown in FIG. 7, the rewiring RM is formed on the surface protectivefilm 10 and the protective film 11, and the rewiring RM is in contactand connected with the pad electrode PA through the openings 10 a and 11a of the surface protective film 10 and the protective film 11. Therewiring RM is configured of a stacked film including a metal barrierfilm 12 and plating films 14 and 15, and the metal barrier film 12 andthe plating films 14 and 15 have the same shape when seen in a planview. The metal barrier film 12 is configured of a stacked filmincluding, for example, a titanium (Ti) film, a titanium nitride (TiN)film and a titanium (Ti) film formed in this order from the bottom, andfilm thicknesses thereof are 10 nm, 50 nm and 10 nm, respectively. Theplating film 14 is made of a copper film and has a film thickness ofabout 5 to 20 μm, and the plating film 15 is made of a nickel film andhas a film thickness of 2 to 3 μm. In addition, a titanium (Ti) film, atitanium nitride (TiN) film, a titanium tungsten (TiW) film, a chromium(Cr) film, a tantalum (Ta) film, a tungsten (W) film, a tungsten nitride(WN) film, a high-melting-point metal film or a noble metal film (Pd,Ru, Pt, Ni or the like) may be used as the metal barrier film 12. Therewiring RM can be referred to also as a conductive layer (a conductivefilm or a wiring conductive layer) connected to the pad electrode PA.

The rewiring RM is a wiring having an extremely low resistance, and hasa film thickness larger (greater) than the film thickness of the padelectrode PA. Further, it is preferable that the film thickness of therewiring RM is at least five to ten times larger than the film thicknessof the pad electrode PA or more. In addition, an interval between theneighboring rewirings RM is larger than an interval between theneighboring pad electrodes PA as shown in FIG. 6.

In addition, a main surface and a side surface of the rewiring RM arecovered with a protective film 16. As shown in FIG. 7, the protectivefilm 16 is interposed between the neighboring rewirings RM, and a gapbetween the neighboring rewirings RM is filled with the protective film16. In other words, the neighboring rewirings RM are physically orelectrically isolated from each other by the protective film 16. Theopening 16 a which exposes a part of the main surface (upper surface) ofthe rewiring RM is formed in the protective film 16. It is importantthat the protective film 16 covers the main surface and the side surfaceof the rewiring RM so as not to expose a shoulder portion and the likeof the rewiring RM, and the protective film 16 is made of an organicinsulating film, for example, a polyimide film and has a film thicknessof 5 to 8 μm.

The bump electrode BE1 is connected to the rewiring RM inside theopening 16 a provided in the protective film 16. The bump electrode BE1is made of, for example, alloy of tin, silver and copper (for example,Sn-1.0Ag-0.5Cu), or may be made of alloy of tin and silver (for example,Sn-1.5Ag).

In addition, an insulating film 17 made of an organic insulating film,for example, a polyimide film is formed around the bump electrode BE1. Afilm thickness of the insulating film 17 is, for example, 25 to 30 μm.The insulating film 17 is formed so as to be in contact with the bumpelectrode BE1 and have a predetermined width to cover the periphery ofthe bump electrode BE1. Namely, the insulating film 17 is selectivelyformed on the protective film 16 so as to cover the periphery of thebump electrode BE1, and a region B in which the insulating film 17 isnot formed and the protective film 16 is exposed is present between theneighboring bump electrodes BE1. The insulating film 17 includes thecircular opening 17 a that exposes the surface of the rewiring RM, andan upper end and a lower end of the opening 17 a are referred to as anopening 17 t and an opening 17 b, respectively. A sidewall of theopening 17 a has a tapered shape, and a diameter of the opening 17 t islarger than a diameter of the opening 17 b. The bump electrode BE1 is incontact with the rewiring RM in the opening 17 b. Though notillustrated, a gold film or a stacked film including a gold film and apalladium film (having a structure in which a palladium film is stackedon a gold film) may be interposed between the bump electrode BE1 and thesurface of the rewiring RM. Incidentally, a film thickness of the gold(Au) film may be set to about 0.03 to 0.2 μm, and a film thickness ofthe palladium (Pd) film may be set to about 0.1 to 0.2 μm.

The insulating film 17 is a dam for controlling the shape of the bumpelectrode BE1, which is provided to increase a ratio of a height (BH)with respect to a width (TD) of the bump electrode BE1 (referred to asan aspect ratio). When the dam is not provided, the bump electrode hasan approximately spherical shape whose lower part is connected to therewiring RM, and thus the aspect ratio of the bump electrode becomesless than 1, and does not become 1 or more. In the present embodiment,the aspect ratio of the bump electrode BE1 can be increased to 1 or moreby providing the insulating film 17 (dam), and the following relationalexpression (Formula 1) is established.

BH/TD≧1  (Formula 1)

In addition, since a width (TD) of the bump electrode BE1 exposed fromthe insulating film 17 can be decreased by increasing the film thicknessof the insulating film 17 and a depth (DH) of the opening 17 a of theinsulating film 17, it is preferable that the depth (DH) of the opening17 a is made larger than ½ of the height (BH) of the bump electrode BE1,and the following relational expression (Formula 2) is established.

DH>½BH  (Formula 2)

Namely, the bump electrode BE1 is made up of a first part surrounded bythe insulating film 17 and a second part exposed from the insulatingfilm 17, and a height of the second part is smaller than a height of thefirst part. Further, a width of the first part is smaller than a widthof the second part. Note that the width of the first part is a width ofthe bump electrode BE1 in the opening 17 t, and the width of the secondpart corresponds to the width (TD) of the bump electrode BE1 and is amaximum width of the bump electrode BE1 exposed from the insulating film17.

In addition, it is preferable to set the diameter (TR) of the opening 17t to be equal to or smaller than twice the depth (DH) of the opening 17a in order to make the bump electrode BE1 have a vertically longcross-sectional shape, and the following relational expression (Formula3) is established.

TR≦2×DH  (Formula 3)

<Manufacturing Method of Semiconductor Device>

FIG. 8 is a process flow diagram showing a part of a manufacturingprocess of the semiconductor device according to the embodiment. FIGS. 9to 15 are cross-sectional views showing a principal part in themanufacturing process of the semiconductor device according to theembodiment.

As shown in FIG. 9, the semiconductor chip CHP having the pad electrodePA formed on the surface thereof is prepared (Step S1 in FIG. 8).

As shown in FIG. 9, a p-type well 2P, an n-type well 2N and an elementisolation trench 3 are formed in the semiconductor substrate 1 made of,for example, p-type monocrystalline silicon, and an element isolationinsulating film 3 a made of, for example, a silicon oxide film is buriedin the element isolation trench 3.

An n-channel MIS transistor (Qn) is formed in the p-type well 2P. Then-channel MIS transistor (Qn) is formed in an active region defined bythe element isolation trench 3, and includes a source region ns and adrain region nd which are formed in the p-type well 2P and a gateelectrode ng which is formed on the p-type well 2P with a gateinsulating film ni interposed therebetween. In addition, a p-channel MIStransistor (Qp) is formed in the n-type well 2N. The p-channel MIStransistor (Qp) includes a source region ps, a drain region pd and agate electrode pg which is formed on the n-type well 2N with a gateinsulating film pi interposed therebetween.

A wiring which is made of metal films and connects semiconductorelements is formed in an upper part of the n-channel MIS transistor (Qn)and the p-channel MIS transistor (Qp). The wiring which connects thesemiconductor elements has a multilayer wiring structure including aboutthree to ten layers in general, and two wiring layers (first-layer Cuwiring 5 and second-layer Cu wiring 7) made of a metal film containingcopper alloy as a main component and one wiring layer (third-layer Alwiring 9) made of a metal film containing Al alloy as a main componentare shown in FIG. 9 as an example of the multilayer wiring. The term“wiring layer” is used in the case of collectively representing aplurality of wirings formed in the respective wiring layers. Withrespect to film thicknesses of the wiring layers, the wiring layer inthe second layer is thicker than the wiring layer in the first layer,and the wiring layer in the third layer is thicker than the wiring layerin the second layer.

Interlayer insulating films 4, 6 and 8 made of silicon oxide films andplugs p1, p2 and p3 which electrically connect the wirings in the threelayers to each other are formed between the n-channel MIS transistor(Qn) and the p-channel MIS transistor (Qn) and the first-layer Cu wiring5, between the first-layer Cu wiring 5 and the second-layer Cu wiring 7,and between the second-layer Cu wiring 7 and the third-layer Al wiring9, respectively.

For example, the interlayer insulating film 4 is formed on thesemiconductor substrate 1 so as to cover the semiconductor elements, andthe first-layer Cu wiring 5 is formed inside an insulating film 5 a onthe interlayer insulating film 4. The first-layer Cu wiring 5 iselectrically connected to the source region ns, the drain region nd andthe gate electrode ng of the n-channel MIS transistor (Qn) serving asthe semiconductor elements through the plugs p1 formed in the interlayerinsulating film 4, for example. In addition, the first-layer Cu wiring 5is electrically connected to the source region ps, the drain region pdand the gate electrode pg of the p-channel MIS transistor (Qp) servingas the semiconductor elements through the plugs p1 formed in theinterlayer insulating film 4. The connection between the gate electrodesng and pg and the first-layer Cu wiring 5 is not illustrated. The plugsp1, p2 and p3 are made of metal films, for example, W (tungsten) films.The first-layer Cu wiring 5 is formed in a wiring trench of theinsulating film 5 a by a damascene method, and the first-layer Cu wiring5 is configured to have a stacked structure including a barrierconductive film and a conductive film which is formed on the barrierconductive film and contains copper as a main component. The barrierconductive film is made of tantalum (Ta), titanium (Ti), ruthenium (Ru),tungsten (W), manganese (Mn), nitrides or silicide nitrides thereof, ora stacked film thereof. The conductive film containing copper as themain component is made of copper (Cu) or copper alloy (alloy containingcopper (Cu) and aluminum (Al), magnesium (Mg), titanium (Ti), manganese(Mn), iron (Fe), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum(Mo), ruthenium (Ru), palladium (Pd), silver (Ag), gold (Au), In(indium), lanthanoid metal, actinoid metal or the like).

The second-layer Cu wiring 7 is electrically connected to thefirst-layer Cu wiring 5 through the plug p2 formed in the interlayerinsulating film 6, for example. The third-layer Al wiring 9 iselectrically connected to the second-layer Cu wiring 7 through the plugp3 formed in the interlayer insulating film 8, for example. The plug p3is made of a metal film, for example, a W (tungsten) film.

The second-layer Cu wiring 7 is formed integrally with the plug p2 inthe interlayer insulating film 6, and the second-layer Cu wiring 7 andthe plug p2 are configured to have a stacked structure including abarrier conductive film and a conductive film which is formed on thebarrier conductive film and contains copper as a main component.Further, the barrier conductive film and the conductive film containingcopper as a main component are made of the same material as that of thefirst-layer Cu wiring 5.

In addition, it is preferable that a barrier insulating film whichprevents the diffusion of copper is provided between the first-layer Cuwiring 5 and the interlayer insulating film 6 and between thesecond-layer Cu wiring 7 and the interlayer insulating film 8, and aSiCN film or a stacked film of a SiCN film and a SiCO film can be usedas the barrier insulating film.

In addition, the third-layer Al wiring 9 is made of an aluminum alloyfilm (for example, an Al film in which Si and Cu are added), but may beformed as a Cu wiring.

Also, the interlayer insulating film 4 is made of a silicon oxide film(SiO₂), but it is a matter of course that the interlayer insulating film4 may be configured of a monolayer film or a stacked film of a siliconoxide film containing carbon (SiOC film), a silicon oxide filmcontaining nitrogen and carbon (SiCON film) and a silicon oxide filmcontaining fluorine (SiOF film).

The surface protective film (protective film, insulating film) 10 whichis made of a monolayer film of, for example, a silicon oxide film or asilicon nitride film or a two-layer film thereof is formed as a finalpassivation film on the third-layer Al wiring 9 which is the wiringlayer in the uppermost layer of the multilayer wiring. Further, thethird-layer Al wiring 9 which is the uppermost wiring layer exposed at abottom portion of the pad opening (opening) 10 a formed in the surfaceprotective film 10 configures the pad electrode (pad, electrode pad) PA.

Next, the protective film (organic insulating film) 11 is formed on thesurface protective film 10 (Step S2 in FIG. 8) as shown in FIG. 10. Notethat the wiring layer, the transistor and the like below the padelectrode PA are not shown in FIG. 10 and the subsequent drawings.Photosensitive polyimide resin is used as the protective film 11. Thephotosensitive polyimide applied onto the surface protective film 10 issubjected to exposure and development, thereby exposing the opening 10 aand the pad electrode PA, and then the photosensitive polyimide is curedby heat treatment. In other words, the protective film 11 having theopening 11 a larger than the opening 10 a and the pad electrode PA isformed by patterning the photosensitive polyimide resin film. Theopenings 10 a and 11 a have a square shape when seen in a plan view.

Next, a seed film 12 is formed on the protective film 11 (Step S3 inFIG. 8). The seed film 12 has a stacked structure including a barrierfilm and a plating seed film on the barrier film. The barrier film ismade of, for example, a titanium film (Ti film), a titanium nitride film(TiN film) and a titanium film (Ti film) which are formed by thesputtering method or the chemical vapor deposition (CVD) method and havefilm thicknesses of 10 nm, 50 nm and 10 nm, and the plating seed film ismade of, for example, a copper (Cu) film which is formed by thesputtering method and has a film thickness of 200 nm. The seed film 12is in contact with the upper surface of the pad electrode PA, and isformed on the sidewalls of the surface protective film 10 and theprotective film 11 constituting the openings 10 a and 11 a and on theupper surfaces of the surface protective film 10 and the protective film11.

Next, a resist film (insulating film, organic insulating film) 13 isformed on the seed film 12 (Step S4 in FIG. 8). A liquid resist or a dryfilm resist can be used as the resist film 13, and a film thicknessthereof is set to, for example, 12 μm. The resist film 13 has anopening, and the opening of the resist film 13 includes the opening 11 aand 10 a.

Next, the plating film 14 is formed in the opening of the resist film13, and then the plating film 15 is formed on the plating film 14 asshown in FIG. 11 (Steps S5 and S6 in FIG. 8). The plating film 14 andthe plating film 15 are formed by the electrolytic plating method. Inthis electrolytic plating process, the seed film 12 functions as a seedlayer. The plating film 14 is a copper (Cu) plating film, and theplating film 15 is a nickel (Ni) plating film. The plating film 14completely fills the openings 10 a and 11 a. The resist film 13 isremoved after forming the plating film 15 (Step S7 in FIG. 8).

Next, the seed film 12 is removed as shown in FIG. 12 (Step S8 in FIG.8). Then, a wet etching process or the like is performed to the seedfilm 12 exposed by removing the resist film 13, thereby removing theseed film 12 in a region exposed from the plating films 14 and 15. Inthis manner, the rewiring RM which is made up of the plating film 15,the plating film 14 and the seed film 12 is formed.

Further, the protective film 16 is formed so as to cover the rewiring RM(Step S9 in FIG. 8). For example, photosensitive polyimide resin is usedas the protective film 16. The photosensitive polyimide applied onto therewiring RM is subjected to exposure, thereby forming the opening 16 awhich exposes a part of the rewiring RM, and then, the photosensitivepolyimide is cured.

Next, the insulating film 17 which covers the part of the rewiring RMexposed through the opening 16 a of the protective film 16 is formed(Step S10 in FIG. 8) as shown in FIG. 12. Photosensitive polyimide resinis used as the insulating film 17, for example. The photosensitivepolyimide applied onto the protective film 16 and the rewiring RM issubjected to exposure and development, thereby forming the insulatingfilm 17. The patterned insulating film 17 has an opening 17 a thatexposes a part of the rewiring RM, and has a ring-shaped patternselectively left only around the opening 17 a. Namely, the insulatingfilm 17 is removed and the protective film 16 is exposed in the region Bon the rewiring RM between the neighboring openings 17 a. However, theinsulating film 17 may be left in the region B between the neighboringopenings 17 a in order to prevent the protective film 16 from beingremoved by over etching and the rewiring RM from being exposed at thetime of patterning the insulating film 17. The insulating film 17 havingthe same film thickness as the insulating film 17 that surrounds theopening 17 a may be left in the region B, or the insulating film 17having a film thickness smaller than that may be left therein. Namely,the insulating film 17 may be left to a degree that prevents theprotective film 16 from being exposed in the region B. In addition, thepatterning of the insulating film 17 may be performed after covering thesurface of the protective film 16 with an insulating film such as asilicon nitride film in the region B.

Next, the bump electrode BE1 is formed as shown in FIG. 13 (Step S11 inFIG. 8). First, a solder ball 18 is supplied to the opening 17 a of theinsulating film 17. The solder ball 18 is a spherical lead-free soldermaterial which is made of, for example, ternary alloy of tin, silver andcopper, and a diameter thereof is 100 μm, 80 μm or 60 μm. The solderball 18 has a diameter larger than that of the opening 17 t, and onesolder ball 18 is supplied to each of the openings 17 a. Next, a reflowprocess (heat treatment) at, for example, 275° C. is performed to thesolder ball 18 to melt the solder ball 18 and to cause solder to flowinto the opening 17 a of the insulating film 17, thereby forming thebump electrode BE1. The bump electrode BE1 is made up of a first part inthe opening 17 a and a second part above the opening 17 a. Namely, it isimportant to use the solder ball 18 having a volume larger than acapacity of the opening 17 a of the insulating film 17 so that thesolder remains also above the opening 17 a of the insulating film 17.

Note that the neighboring bump electrodes BE1 may be formed in differentprocesses. In this case, for example, among the lines of the pluralityof bump electrodes BE1 shown in FIG. 5 (for example, lines extending inthe Y direction), the bump electrodes BE1 in odd lines are first formed,and the bump electrodes BE1 in even lines are formed thereafter.Specifically, after the solder balls 18 are arranged in the bumpelectrode mounting portions in the odd lines, the reflow is performed toform the bump electrodes BE1 in the odd lines, and thereafter, the bumpelectrodes BE1 in the even lines are formed through the similar steps.According to this method, it is possible to improve the mountingaccuracy of the solder ball 18 on the opening 17 a of the insulatingfilm 17.

Next, a board mounting process (Step S12 in FIG. 8) and a fillingprocess of the sealing material UF (Step S13 in FIG. 8) are performed asshown in FIGS. 14 and 15. As shown in FIG. 14, the semiconductor chipCHP is mounted onto the wiring board WB so that the main surface of thesemiconductor chip CHP opposes the front surface of the wiring board WBand the bump electrode BE1 and the terminal TA positionally correspondto each other. Here, a pre-solder 19 is formed on a surface of theterminal TA of the wiring board WB. The ternary lead-free soldermaterial made of tin-silver-copper (Sn—Ag—Cu) can be used also as thepre-solder 19.

Next, as shown in FIG. 15, the semiconductor chip CHP and the wiringboard WB are subjected to the reflow at, for example, 270 to 280° C., sothat the rewiring RM and the terminal TA are connected by the bumpelectrode BE2 formed by melting the bump electrode BE1 and thepre-solder 19. Namely, the semiconductor chip CHP is connected to thewiring board WB by the bump electrode BE2.

Next, the sealing material UF is caused to flow into a gap between themain surface of the semiconductor chip CHP and the front surface of thewiring board WB and between the bump electrodes BE2, and thereafter, theheat treatment is performed to evaporate the solvent, thereby sealingthe gap between the semiconductor chip CHP and the wiring board WB withthe sealing material UF as shown in FIG. 15. The sealing material UF isin contact with the protective film 16 and the insulating film 17 of thesemiconductor chip CHP and the solder resist film SR1 of the wiringboard WB. Further, the sealing material UF is in contact with the entireperiphery of the bump electrode BE2 and covers the bump electrode BE2.In other words, the sealing material UF completely covers the sidesurface of the bump electrode BE2 that is exposed from the insulatingfilm 17 and the solder resist film SR1. The sealing material UF fills aspace formed by the semiconductor chip CHP, the wiring board WB and thebump electrodes BE2 without any gap or void.

Here, the film thickness of the insulating film 17 (the film thicknesson the protective film 16 or on the rewiring RM) is larger than the filmthickness of the protective film 16 (the film thickness on the rewiringRM). According to this configuration, since it is possible to deepen theregion B of FIG. 15, an inflow path (cross-sectional area of an inflowregion) of the sealing material UF between the bump electrodes BE2 canbe widened, and the generation of the void can be reduced.

In addition, the height of the bump electrode BE2 becomes about 80% ofthe height (BH) of the bump electrode BE1 after the board mounting, butthe depth of the opening 17 a of the insulating film is not changed, andthus, the above-described relational expression 2 is still establishedafter the board mounting. Similarly, the above-described relationalexpression 3 is still established after the board mounting. In addition,it is preferable that the aspect ratio of the bump electrode BE2 isequal to or more than 1.

In addition, the bump electrode BE2 is made up of a first partsurrounded by the insulating film 17 and a second part exposed from theinsulating film 17, and it is preferable that a height of the secondpart is smaller than a height of the first part. Further, a width of thefirst part is smaller than a width of the second part. Note that thewidth of the first part is a width of the widest portion of the bumpelectrode BE2 in the opening 17 a, and the width of the second part is awidth of the widest portion of the bump electrode BE2 exposed from theinsulating film 17.

The semiconductor device SA according to the present embodiment iscompleted through the above-described manufacturing process.

<Characteristics of Semiconductor Device According to Present Embodimentand Manufacturing Method Thereof>

In the semiconductor device SA according to the present embodiment, thebump electrode BE2 is made up of the first part whose periphery issurrounded by the insulating film 17 and the second part exposed(protruding) from the insulating film 17. According to thisconfiguration, it is possible to decrease the width of the bumpelectrode BE2 while increasing the height of the bump electrode BE2 ascompared to the case in which the insulating film 17 is not provided. Inother words, it is possible to increase a distance between theneighboring bump electrodes BE2.

Since it is possible to mitigate the stress applied to the bumpelectrode BE2 due to the difference in coefficient of thermal expansionbetween the semiconductor chip CHP and the wiring board WB by increasingthe height of the bump electrode BE2, it is possible to reduce theconnection failure between the bump electrode BE2 and the semiconductorchip CHP and between the bump electrode BE2 and the wiring board WB. Inaddition, since the insulating film 17 is made of a polyimide film, itis possible to mitigate the stress applied to the bump electrode BE2.

Also, since the distance between the neighboring bump electrodes BE2 isincreased, it is possible to prevent the short circuit between theneighboring bump electrodes BE2. Further, it is possible to prevent thegeneration of the void in the sealing material UF that fills the gapbetween the bump electrodes BE2.

In addition, the film thickness of the insulating film 17 is made largerthan the film thickness of the protective film 16 that covers therewiring RM in the semiconductor device SA according to the embodiment.Also, the insulating film 17 is formed in the ring shape around the bumpelectrode BE2. According to this configuration, it is possible toincrease a contact area of the sealing material UF and the semiconductorchip CHP or the wiring board WB between the bump electrodes BE2, andthus the sealing strength can be improved.

In addition, in the manufacturing method of the semiconductor device SAaccording to the present embodiment, the solder ball 18 is placed on theopening 17 a in the center portion of the insulating film 17, and then,the reflow is performed to form the bump electrode BE1 having the firstpart surrounded by the insulating film 17 and the second part exposedfrom the insulating film 17. Thereafter, the bump electrode BE1 isconnected to the terminal TA of the wiring board WB to form the bumpelectrode BE2, and the sealing material UF is supplied to fill the gapbetween the bump electrodes BE2.

According to the above-described manufacturing method, since it ispossible to increase the cross-sectional area of the inflow path of thesealing material UF at the time of supplying the sealing material UF tofill the gap between the bump electrodes BE2, it is possible to preventthe generation of the void in the sealing material UF, and theconnection reliability between the bump electrode BE2 and thesemiconductor chip CHP and between the bump electrode BE2 and the wiringboard WB can be improved. Herein, the expression “in the sealingmaterial UF” includes an interface between the sealing material UF andthe bump electrode BE2 and an interface between the sealing material UFand the wiring board WB or the semiconductor chip CHP.

In addition, since the insulating film 17 is selectively formed onlyaround the bump electrode BE1 on the protective film 16, it is possibleto increase the cross-sectional area of the inflow path of the sealingmaterial UF. In addition, the film thickness of the insulating film 17is made larger than the film thickness of the protective film 16, andthus, it is possible to further increase the cross-sectional area of theinflow path of the sealing material UF. Accordingly, it is possible toprevent the generation of the void in the sealing material UF.

Note that the above-described embodiment has the structure in which therewiring RM is connected to the pad electrode PA and the bump electrodeBE1 is formed at the end portion of the rewiring RM, but the insulatingfilm 17 according to the present embodiment may be applied at the timeof forming the bump electrode BE1 on the pad electrode PA via a barriermetal layer without using the rewiring RM.

Modification Example 1

The modification Example 1 is a modification example of theabove-described embodiment and is different from the above-describedembodiment in that the board mounting is carried out after mounting asolder ball on a wiring board. FIG. 16 is a cross-sectional view showinga principal part in a manufacturing process of a semiconductor device ofthe Modification Example 1.

After Steps S1 to S10 in the process flow diagram shown in FIG. 8 areexecuted, board mounting corresponding to Step S12 is executed withoutexecuting Step S11. At this time, the solder ball 18 is arranged on theterminal TA of the wiring board WB as shown in FIG. 16 without formingthe bump electrode BE1 on the semiconductor chip CHP. Then, Step S13 isexecuted after the semiconductor chip CHP is arranged on the wiringboard WB and the reflow is carried out, so that the semiconductor deviceaccording to the Modification Example 1 having the similar structure asthe semiconductor device in FIG. 15 is completed.

According to the Modification Example 1, since it is possible to omitthe process of forming the bump electrode BE1 (Step S11) of FIG. 8, themanufacturing method can be simplified. Further, since it is possible toomit the reflow process, the thermal load to the semiconductor chip CHPcan be reduced.

In addition, the bump electrode BE2 shown in FIG. 15 is formed when thesolder ball 18 is melted and flows into the opening 17 a of theinsulating film 17 in the reflow process of the board mounting.According to this manufacturing method, the semiconductor chip CHP andthe wiring board WB are positioned in a self-aligned manner.

Modification Example 2

The Modification Example 2 is a modification example of theabove-described embodiment, and corresponds to the example in which theabove-described embodiment and the Modification Example 1 are combined.FIG. 17 is a cross-sectional view showing a principal part in amanufacturing process of a semiconductor device of the ModificationExample 2.

The bump electrodes BE1 in the odd lines in the X direction of FIG. 5are formed in the same manner as the above-described embodiment. Then,the bump electrodes BE2 in the even lines are formed according to themethod of the Modification Example 1. Namely, Steps S1 to S11 in FIG. 8are executed to prepare the bump electrodes BE1 in the odd lines of thesemiconductor chip CHP. Further, the wiring board WB in which the solderballs 18 are arranged on the terminals TA of the wiring board WBcorresponding to the bump electrode mounting portions in the even linesof the semiconductor chip CHP is prepared. Next, the semiconductor chipCHP is mounted on the wiring board WB and the reflow is carried out,thereby executing the board mounting process. Then, the filling processof the sealing material UF (Step S13) of FIG. 8 is executed, so that thesemiconductor device according to the Modification Example 2 having thesimilar structure as the semiconductor device in FIG. 15 ismanufactured.

Modification Example 3

The Modification Example 3 is a modification example of theabove-described embodiment and is different from the above-describedembodiment in that the dummy bump electrode DBE1 is arranged at thecorner portion of the semiconductor chip CHP. FIGS. 18 and 19 arecross-sectional views showing a principal part in a manufacturingprocess of a semiconductor device of the Modification Example 3.

As shown in FIG. 5, the dummy bump electrode DBE1 is arranged at each ofthe four corner portions of the semiconductor chip CHP. The dummy bumpelectrode DBE1 is larger than the bump electrode BE1, and the areathereof is about 1.5 times the area of the bump electrode BE1.

The semiconductor device according to the Modification Example 3 iscompleted by executing Steps S1 to S13 of FIG. 8, but the dummy bumpelectrode DBE1 is formed from the two solder balls 18 in the process offorming the bump electrode BE1 in Step S11. As shown in FIG. 18, a widthof the dummy bump electrode DBE1 in the long-axis or short-axisdirection is larger than that of the bump electrode BE1.

Next, Steps S12 and S13 are executed, but since the volume of the dummybump electrode DBE1 is larger than that of the bump electrode BE1, thegap between the semiconductor chip CHP and the wiring board WB can bedetermined by a height of the dummy bump electrode DBE2. Namely, the gapbetween the semiconductor chip CHP and the wiring board WB is larger inthe Modification Example 3 than in the case of the above-describedembodiment. In this manner, since the cross-sectional shape of the bumpelectrode BE2 can be changed from a drum shape to an hourglass shape, itis possible to further improve a margin for short-circuit between theneighboring bump electrodes BE1.

In addition, since the dummy bump electrode DBE2 with the large width isarranged at the corner portion of the semiconductor chip CHP and thecross-sectional shape of the bump electrode BE2 is changed to thehourglass shape, the effect of mitigating the stress can be furtherimproved.

In the foregoing, the invention made by the inventor of the presentinvention has been concretely described based on the embodiments.However, it is needless to say that the present invention is not limitedto the foregoing embodiments and various modifications and alterationscan be made within the scope of the present invention.

In addition, some of the contents described in the above-describedembodiment will be described below.

APPENDIX 1

A manufacturing method of a semiconductor device includes the steps of:

(a) preparing a semiconductor substrate having a first conductive layerand a second conductive layer which are formed on a main surface thereofand a first insulating film which covers the first conductive layer andthe second conductive layer;

(b) forming a second insulating film which covers the first insulatingfilm and has a first opening which exposes a surface of the firstconductive layer and a second opening which exposes a surface of thesecond conductive layer;

(c) arranging a first solder ball in the first opening and a secondsolder ball in the second opening and performing heat treatment to thefirst solder ball and the second solder ball, thereby forming a firstbump electrode made up of a first part in the first opening and a secondpart on the first opening and a second bump electrode made up of a thirdpart in the second opening and a fourth part on the second opening; and

(d) connecting the first bump electrode to a first terminal of a wiringboard and the second bump electrode to a second terminal of the wiringboard.

APPENDIX 2

The manufacturing method of a semiconductor device described in Appendix1 further includes the step of:

(e) filling a gap between the semiconductor substrate and the wiringboard with a sealing material, and

the sealing material is supplied so as to fill a gap between the firstbump electrode and the second bump electrode.

APPENDIX 3

In the manufacturing method of a semiconductor device described inAppendix 1, the second insulating film is partially removed in a regionbetween the first opening and the second opening in the step (b).

APPENDIX 4

In the manufacturing method of a semiconductor device described inAppendix 1, the step (c) includes the steps of:

(c1) arranging the first solder ball in the first opening and performingfirst heat treatment to the first solder ball, thereby forming the firstbump electrode; and

(c2) arranging the second solder ball in the second opening andperforming second heat treatment different from the first heat treatmentto the second solder ball, thereby forming the second bump electrode.

APPENDIX 5

A manufacturing method of a semiconductor device includes the steps of:

(a) preparing a semiconductor substrate having a first conductive layerand a second conductive layer which are formed on a main surface thereofand a first insulating film which covers the first conductive layer andthe second conductive layer;

(b) forming a second insulating film which covers the first insulatingfilm and has a first opening which exposes a surface of the firstconductive layer and a second opening which exposes a surface of thesecond conductive layer;

(c) preparing a wiring board in which a first solder ball is arranged ona first terminal and a second solder ball is arranged on a secondterminal, the terminals being formed on a surface of the wiring board;and

(d) arranging the semiconductor substrate on the wiring board andmelting the first solder ball and the second solder ball by performingheat treatment, thereby forming a first bump electrode which connectsthe first conductive layer and the first terminal and a second bumpelectrode which connects the second conductive layer and the secondterminal.

APPENDIX 6

The manufacturing method of a semiconductor device described in Appendix5 further includes the step of:

(e) filling a gap between the semiconductor substrate and the wiringboard with a sealing material, and

the sealing material is supplied so as to fill a gap between the firstbump electrode and the second bump electrode.

APPENDIX 7

A manufacturing method of a semiconductor device includes the steps of:

(a) preparing a semiconductor substrate having a first conductive layerand a second conductive layer which are formed on a main surface thereofand a first insulating film which covers the first conductive layer andthe second conductive layer;

(b) forming a second insulating film which covers the first insulatingfilm and has a first opening which exposes a surface of the firstconductive layer and a second opening which exposes a surface of thesecond conductive layer;

(c) arranging a first solder ball in the first opening and performingheat treatment to the first solder ball, thereby forming a first bumpelectrode made up of a first part in the first opening and a second parton the first opening;

(d) preparing a wiring board which has a first terminal and a secondterminal formed on a surface thereof and in which a second solder ballis arranged on the second terminal; and

(e) arranging the semiconductor substrate on the wiring board andperforming heat treatment, thereby connecting the first bump electrodeto the first terminal of the wiring board and melting the second solderball to form a second bump electrode which connects the secondconductive layer and the second terminal.

APPENDIX 8

The manufacturing method of a semiconductor device described in Appendix7 further includes the step of:

(f) filling a gap between the semiconductor substrate and the wiringboard with a sealing material, and

the sealing material is supplied so as to fill a gap between the firstbump electrode and the second bump electrode.

What is claimed is:
 1. A semiconductor device comprising: asemiconductor substrate; a conductive layer formed on the semiconductorsubstrate; a first insulating film which is formed on the conductivelayer and covers the conductive layer; a second insulating film which isformed on the first insulating film and includes an opening whichexposes a part of a surface of the conductive layer; a bump electrodewhich is made up of a first part which is in contact with the conductivelayer and positioned in the opening and a second part which ispositioned on the opening and exposed from the second insulating film; aterminal which is connected to the bump electrode and is formed on asurface of a wiring board; and a sealing material which fills a gapbetween the semiconductor substrate and the wiring board.
 2. Thesemiconductor device according to claim 1, wherein a height of the firstpart is larger than a height of the second part.
 3. The semiconductordevice according to claim 1, wherein a width of the first part issmaller than a width of the second part.
 4. The semiconductor deviceaccording to claim 1, wherein the second insulating film covers aperiphery of the first part of the bump electrode.
 5. The semiconductordevice according to claim 4, wherein a film thickness of the secondinsulating film is larger than a film thickness of the first insulatingfilm.
 6. The semiconductor device according to claim 4, wherein thesealing material is in contact with the first insulating film on anouter side of the second insulating film which covers the periphery ofthe first part of the bump electrode.
 7. The semiconductor deviceaccording to claim 1, wherein the sealing material covers a periphery ofthe second part of the bump electrode and is in contact with a sidesurface of the second part.
 8. The semiconductor device according toclaim 1 further comprising: a third insulating film which covers thesurface of the wiring board and exposes the terminal.
 9. Thesemiconductor device according to claim 8, wherein the sealing materialis in contact with the third insulating film.
 10. The semiconductordevice according to claim 1 further comprising: a pad electrode providedon the semiconductor substrate, wherein the conductive layer isconnected to the pad electrode.
 11. The semiconductor device accordingto claim 10, wherein a film thickness of the conductive layer is largerthan a film thickness of the pad electrode.
 12. The semiconductor deviceaccording to claim 1, wherein the second insulating film is made of apolyimide film.
 13. The semiconductor device according to claim 1,wherein the first insulating film is made of a polyimide film.
 14. Thesemiconductor device according to claim 1, wherein the bump electrode ismade of ternary alloy containing tin, silver and copper.
 15. Thesemiconductor device according to claim 1, wherein the semiconductorsubstrate has a rectangular shape, the semiconductor device furthercomprising: a dummy bump electrode that is arranged at a corner portionof the semiconductor substrate.